<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<style>
    .box{ background:skyblue; overflow: hidden }
    .kid{ width: 100px;height: 100px; float:left;}
    .kid1{ background: yellow; }
    .kid2{ background: orange; }
    .wrap{ width: 300px; height: 150px; background: blue; color: white; }
</style>

<body>
<div class="box">
    <div class="kid kid1">子元素1</div>
    <div class="kid kid2">子元素2</div>
</div>
<div class="wrap">其他部分</div>
</body>
</body>
</html>